I have unity, gnome-shell and xubuntu on my laptop. They all have their favorite preinstalled programs it seems. Do I really need three text editors for example? Could I remove two and just have the other desktops use the one I keep? It seems as though I could get rid of all video playback programs as well and just use vlc for example. Am I going to mess something up? I am new to all this.
I would be careful with removing seemingly superfluous programs. Other packages, even unrelated ones coming with the DE might depend on them. On LXDE for instance you can't remove
gedit) without deleting essential packages such as
lxinput and other ones.
Save for these dependency issues there is no reason why you shouldn't be able to remove duplicate applications. Just make sure that you can configure the DE to use a replacement of your choice, e.g.
gnome-calculator instead of
If it's not the wasted disk space that bothers you, but clutter in the respective DEs menus, you can always add the
OnlyShowIn= parameter to the application launchers in question. See here for a tutorial on Kubuntu entries.